Re: Precedence Misunderstanding

From	Keith Thompson <kst-u@mib.org>
Newsgroups	comp.lang.c
Subject	Re: Precedence Misunderstanding
Date	2012-07-18 13:26 -0700
Organization	None to speak of
Message-ID	<ln1uk8dde9.fsf@nuthaus.mib.org> (permalink)
References	(4 earlier) <ju6l4f$gvf$1@speranza.aioe.org> <87y5mhgfxb.fsf@blp.benpfaff.org> <ju6rvj$2t8$1@speranza.aioe.org> <87txx5gdzn.fsf@blp.benpfaff.org> <ju6v9v$av2$1@speranza.aioe.org>

Show all headers | View raw

Rui Maciel <rui.maciel@gmail.com> writes:
> Ben Pfaff wrote:
>> The article I replied to talked about floating-point numbers and
>> fenv_t.  Certainly that's not covered in basic algebra.  Are you
>> referring to some other article?
>
> Algebra is a branch of mathematics which covers operators and relations 
> between sets.  These sets aren't limited to the real numbers set, and the 
> operators aren't limited to the basic mathematical operators that take real 
> values as operands.  In fact, typically the first contact with algebra tends 
> not to involve real numbers at all, or basic math operators.  Take, for 
> example, how Venn diagrams tend to be presented in kindergarten.
>
> Regarding "side effects", the concepts which I've referred to are indeed 
> covered, and they tend to be covered right in the very first explanation of 
> what a function is supposed to be.  Once you were taught that a function f 
> maps elements in a set A to elements in a set B, you covered all the math 
> that is needed to explain and understand "side effects".  No new math is 
> needed to describe a function assigning a certain value to a flag, or 
> returning a different value depending on the value stored in any other flag.

In my experience, a mathematical operator or function takes zero
or more operands and yields a value. The operands/arguments are
members of your "set A", and the result is a member of your "set B"
(either of which may or may not be numbers).

If an operator had "side effects" in the C sense, then those side
effects would normally be described as part of the result.

In C, side effects are effects (changes of state) involving something
other than the result of the function or operator. I have not seen
a similar concept applied in mathematics; instead, any such effects
are part of the result (since mathematics is not limited by C's
type system). For example, a mathematical function's result might
be the entire state of a machine, if that's what it's modelling --
and in that case I wouldn't call anything that's part of the machine
state a "side effect".

Do you have a specific concrete example of "side effects" in basic
mathematics?

--  
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
    Will write code for food.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

Thread

Precedence Misunderstanding Charles Richmond <frizzle@aquaporin4.com> - 2012-07-16 23:18 -0500
  Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-16 21:54 -0700
    Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-16 22:13 -0700
      Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-16 22:36 -0700
        Re: Precedence Misunderstanding Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-17 13:57 +0100
    Re: Precedence Misunderstanding "Charles Richmond" <numerist@aquaporin4.com> - 2012-07-17 13:35 -0500
      Re: Precedence Misunderstanding "io_x" <a@b.c.invalid> - 2012-07-17 20:48 +0200
      Re: Precedence Misunderstanding Robert Wessel <robertwessel2@yahoo.com> - 2012-07-17 13:45 -0500
      Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-17 12:27 -0700
        Re: Precedence Misunderstanding Willem <willem@toad.stack.nl> - 2012-07-17 20:20 +0000
      Re: Precedence Misunderstanding Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-17 20:34 +0100
        Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-17 12:39 -0700
          Re: Precedence Misunderstanding Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-17 20:57 +0100
        Re: Precedence Misunderstanding Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-17 20:48 +0100
          Re: Precedence Misunderstanding Philip Lantz <prl@canterey.us> - 2012-07-17 21:12 -0700
            Re: Precedence Misunderstanding Ike Naar <ike@iceland.freeshell.org> - 2012-07-18 07:14 +0000
              Re: Precedence Misunderstanding "BartC" <bc@freeuk.com> - 2012-07-18 10:11 +0100
                Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-18 09:18 -0700
                Re: Precedence Misunderstanding Rui Maciel <rui.maciel@gmail.com> - 2012-07-18 18:10 +0100
                Re: Precedence Misunderstanding Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-18 18:27 +0100
                Re: Precedence Misunderstanding Rui Maciel <rui.maciel@gmail.com> - 2012-07-18 18:53 +0100
                Re: Precedence Misunderstanding Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-18 21:07 +0100
                Re: Precedence Misunderstanding Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-07-19 20:47 +0300
              Re: Precedence Misunderstanding Philip Lantz <prl@canterey.us> - 2012-07-18 23:54 -0700
                Re: Precedence Misunderstanding Ike Naar <ike@sverige.freeshell.org> - 2012-07-19 07:21 +0000
      Re: Precedence Misunderstanding "BartC" <bc@freeuk.com> - 2012-07-17 20:42 +0100
      Re: Precedence Misunderstanding Willem <willem@toad.stack.nl> - 2012-07-17 20:38 +0000
        Re: Precedence Misunderstanding Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-07-19 20:54 +0300
          Re: Precedence Misunderstanding Willem <willem@toad.stack.nl> - 2012-07-19 22:02 +0000
      Re: Precedence Misunderstanding pete <pfiland@mindspring.com> - 2012-07-17 22:31 -0400
      Re: Precedence Misunderstanding Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-07-18 00:35 -0700
    Re: Precedence Misunderstanding Rui Maciel <rui.maciel@gmail.com> - 2012-07-17 22:16 +0100
      Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-17 14:22 -0700
        Re: Precedence Misunderstanding Rui Maciel <rui.maciel@gmail.com> - 2012-07-18 16:35 +0100
          Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-18 10:03 -0700
            Re: Precedence Misunderstanding Rui Maciel <rui.maciel@gmail.com> - 2012-07-18 18:32 +0100
              Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-18 10:45 -0700
                Re: Precedence Misunderstanding Rui Maciel <rui.maciel@gmail.com> - 2012-07-18 19:29 +0100
                Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-18 11:45 -0700
                Re: Precedence Misunderstanding Keith Thompson <kst-u@mib.org> - 2012-07-18 13:26 -0700
                Re: Precedence Misunderstanding Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-07-19 00:51 -0700
              Re: Precedence Misunderstanding Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-07-19 00:11 -0700
  Re: Precedence Misunderstanding Robert Wessel <robertwessel2@yahoo.com> - 2012-07-17 00:05 -0500
  Re: Precedence Misunderstanding Ike Naar <ike@iceland.freeshell.org> - 2012-07-17 07:40 +0000

csiph-web